Sodium-ion battery positive electrode material and preparation method thereof

Abstract

The invention relates to the technical field of sodium-ion batteries, in particular to a sodium-ion battery positive electrode material and a preparation method thereof. The sodium ion battery positive electrode material is Ti and Cl doped Na4VMn (PO4) 3, and the molar ratio of Na to Ti in the sodium ion battery positive electrode material is 4: (0.05-0.1); the molar ratio of Na to Cl is 4: (0.05-0.1). According to the sodium-ion battery positive electrode material provided by the invention, a titanium element and chlorine element synergistic co-doping mode is adopted, so that the ginger-Taylor distortion caused by manganese ions in the charging and discharging process can be inhibited, the lattice stress can be reduced, and the stability of the material structure can be enhanced; meanwhile, the dissolution of manganese under a high-rate cycle condition can be inhibited, and the loss of active substances and the side reaction of electrolyte are reduced, so that the electrochemical stability and the structural integrity of the electrode material are improved, and the sodium ion battery containing the positive electrode material has relatively high specific capacity, excellent rate capability and cycle stability.

Description

A sodium-ion battery cathode material and its preparation method Technical Field

[0001] This invention relates to the field of sodium-ion battery technology, specifically to a sodium-ion battery cathode material and its preparation method. Background Technology

[0002] The cathode materials for sodium-ion batteries mainly fall into four categories: transition metal layered oxides, Prussian blue analogues, polyanionic compounds, and tunnel oxides. NASICON's polyanionic Na3V2(PO4)3 sodium-ion battery has attracted considerable attention due to its excellent electrochemical performance, with a V... 3+ / V 4+ The redox reaction, at a voltage of approximately 3.4 V, exhibits electrochemical activity capable of releasing / embedding two sodium ions; simultaneously, it possesses strong inductive effects and covalently bonded polyanionic groups (such as PO4). 3- This can induce a higher operating potential and suppress oxygen evolution, thereby increasing the energy density of NASICON polyanion cathodes in sodium-ion batteries and enhancing their safety.

[0003] To extend the operating voltage and improve the energy density of NASICON-type sodium-ion batteries, Mn with a lower valence state was used. 2+ Replace V 3+ The sodium content can be increased to four sodium ions, thereby activating more than two sodium ions at high operating potentials. This allows sodium ions to participate in electrochemical reactions more effectively, leading to the successful synthesis of the cathode material Na4VMn(PO4)3. Due to its stable crystal structure and high sodium ion mobility, this material can significantly improve the battery's operating voltage and energy density, thus enhancing overall electrochemical performance.

[0004] However, during long-term cycling, manganese is prone to Zynthia distortion or dissolution, which leads to a significant decrease in the capacity and cycle performance of sodium-ion batteries at high rates, posing a serious challenge to their practical application. Summary of the Invention

[0005] The purpose of this invention is to solve the problem that manganese is prone to Gyntelle distortion or dissolution in the prior art, which leads to a significant decrease in the capacity and cycle performance of sodium-ion batteries at high rates, and to provide a sodium-ion battery cathode material and its preparation method.

[0006] In a first aspect, the present invention provides a sodium-ion battery cathode material, wherein the sodium-ion battery cathode material is Ti and Cl doped Na4VMn(PO4)3; the molar ratio of Na to Ti in the sodium-ion battery cathode material is 4:(0.05-0.1); the molar ratio of Na to Cl in the sodium-ion battery cathode material is 4:(0.05-0.1).

[0007] Secondly, the present invention provides a method for preparing a sodium-ion battery cathode material, comprising the following steps: S1, mixing a sodium source, a vanadium source, a manganese source, a titanium source, and a chlorine source with a first solvent to obtain a first solution; S2, mixing a phosphorus source, citric acid, and a second solvent to obtain a second solution; S3, mixing the first solution and the second solution, and then drying, grinding, and calcining to obtain the cathode material of the sodium-ion battery.

[0008] In some alternative embodiments, the chlorine source includes at least one of sodium chloride or ammonium chloride.

[0009] In some alternative embodiments, the titanium source includes at least one of ethyl titanate, titanium acetylacetonate, or tetrabutyl titanate.

[0010] In some alternative embodiments, the sodium source includes at least one of sodium hydroxide, sodium carbonate, sodium bicarbonate, sodium acetate, sodium nitrate, or sodium oxalate.

[0011] In some alternative embodiments, the manganese source includes at least one of manganese acetate, manganese sulfate, manganese nitrate, manganese acetylacetone, manganese oxalate, manganese carbonate, or manganese oxide.

[0012] In some alternative embodiments, the molar ratio of sodium, vanadium, manganese, titanium, and chlorine in the first solution is 4:1:0.9:(0.05-0.1):(0.05-0.1).

[0013] In some alternative embodiments, the concentration of vanadium in the first solution is 0.5 mol / L to 1 mol / L.

[0014] In some alternative embodiments, the phosphorus source includes at least one of phosphoric acid, ammonium dihydrogen phosphate, diammonium hydrogen phosphate, or ammonium phosphate.

[0015] In some alternative embodiments, the molar ratio of carbon atoms in the citric acid to vanadium in the vanadium source is (1-1.5):(0.5-1).

[0016] In some alternative embodiments, the molar ratio of phosphorus in the phosphorus source to vanadium in the vanadium source is (2.8-2.9):(0.9-1.0).

[0017] In some alternative embodiments, the concentration of phosphorus in the phosphorus source in the second solution is 0.8 mol / L to 1.1 mol / L.

[0018] In some alternative embodiments, the first solvent is at least one of ethanol or water; the second solvent is at least one of ethanol or water.

[0019] In some optional embodiments, in S3, the mixing process involves adding the second solution to the first solution; the addition is preferably done dropwise.

[0020] In some optional embodiments, in S3, the drying temperature is 50°C-110°C; the drying time is 18h-24h.

[0021] In some alternative embodiments, the grinding time is 10 min to 60 min.

[0022] In some optional embodiments, the calcination temperature is 300℃-700℃, and the calcination time is 4h-8h.

[0023] Thirdly, the present invention provides a sodium-ion battery, wherein the sodium-ion battery comprises the sodium-ion battery positive electrode material described in the first aspect or the positive electrode material prepared by the method for preparing the sodium-ion battery positive electrode material described in the second aspect.

[0024] The technical solution of this invention has the following advantages: The sodium-ion battery cathode material provided by this invention is Ti and Cl-doped Na₄VMn(PO₄)₃, wherein the molar ratio of Na to Ti in the sodium-ion battery cathode material is 4:(0.05-0.1); the molar ratio of Na to Cl is 4:(0.05-0.1). The sodium-ion battery cathode material provided by this invention employs a synergistic co-doping method of titanium and chlorine elements. On the one hand, this can suppress the Jan Taylor distortion induced by manganese ions during charging and discharging, reduce lattice stress, and enhance the stability of the material structure; on the other hand, it can suppress the dissolution of manganese under high-rate cycling conditions, reduce the loss of active materials and electrolyte side reactions, thereby significantly improving the electrochemical stability and structural integrity of the electrode material. This results in sodium-ion batteries containing this cathode material possessing high specific capacity and excellent rate performance, while maintaining excellent cycle stability. Attached Figure Description

[0025] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0026] Figure 1 is a charge-discharge diagram of the coin cells prepared in Example 1 and Comparative Examples 1-3 of the present invention. Detailed Implementation

[0027] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, only the parts relevant to the present invention are shown in the drawings, not the entire structure.

[0028] In a first aspect, the present invention provides a sodium-ion battery cathode material, wherein the sodium-ion battery cathode material is Ti and Cl doped Na4VMn(PO4)3; the molar ratio of Na to Ti in the sodium-ion battery cathode material is 4:(0.05-0.1); the molar ratio of Na to Cl in the sodium-ion battery cathode material is 4:(0.05-0.1).

[0029] By employing a synergistic co-doping method with titanium and chlorine, the Gaines-Taylor distortion induced by manganese ions during charging and discharging can be suppressed, reducing lattice stress and enhancing the stability of the material structure. On the other hand, it can suppress the dissolution of manganese under high-rate cycling conditions, reducing the loss of active materials and side reactions of the electrolyte. This significantly improves the electrochemical stability and structural integrity of the electrode material, enabling sodium-ion batteries containing this cathode material to have high specific capacity and excellent rate performance, while maintaining excellent cycle stability.

[0030] Secondly, the present invention provides a method for preparing a sodium-ion battery cathode material, comprising the following steps: S1, mixing a sodium source, a vanadium source, a manganese source, a titanium source, and a chlorine source with a first solvent to obtain a first solution; S2, mixing a phosphorus source, citric acid, and a second solvent to obtain a second solution; S3, mixing the first solution and the second solution, and then drying, grinding, and calcining to obtain the cathode material of the sodium-ion battery.

[0031] In some alternative embodiments, the chlorine source includes at least one of sodium chloride or ammonium chloride.

[0032] In some alternative embodiments, the titanium source includes at least one of ethyl titanate, titanium acetylacetonate, or tetrabutyl titanate.

[0033] In some alternative embodiments, the sodium source includes at least one of sodium hydroxide, sodium carbonate, sodium bicarbonate, sodium acetate, sodium nitrate, or sodium oxalate.

[0034] In some alternative embodiments, the manganese source includes at least one of manganese acetate, manganese sulfate, manganese nitrate, manganese acetylacetone, manganese oxalate, manganese carbonate, or manganese oxide.

[0035] In some alternative embodiments, the molar ratio of sodium, vanadium, manganese, titanium, and chlorine in the first solution is 4:1:0.9:(0.05-0.1):(0.05-0.1).

[0036] In some alternative embodiments, the concentration of vanadium in the first solution is 0.5 mol / L to 1 mol / L. Examples include 0.5 mol / L, 0.6 mol / L, 0.7 mol / L, 0.8 mol / L, 0.9 mol / L, 1.0 mol / L, or any range of the above values.

[0037] In some alternative embodiments, the phosphorus source includes at least one of phosphoric acid, ammonium dihydrogen phosphate, diammonium hydrogen phosphate, or ammonium phosphate.

[0038] In some alternative embodiments, the molar ratio of carbon atoms in the citric acid to vanadium in the vanadium source is (1-1.5):(0.5-1), such as 1:0.5, 1:0.6, 1:0.7, 1:0.8, 1:0.9, 1:1.0, 1.3:0.5, 1.3:0.7, 1.3:1, 1.5:0.5, 1.5:0.7, 1.5:1, etc., or a range of any of the above values.

[0039] In some alternative embodiments, the molar ratio of phosphorus in the phosphorus source to vanadium in the vanadium source is (2.8-2.9):(0.9-1.0), such as 2.81:0.9, 2.82:0.9, 2.85:0.9, 2.87:0.9, 2.9:0.9, 2.82:1.0, 2.84:1.0, 2.88:1.0, 2.9:1.0, etc., or a range of any of the above values.

[0040] In some alternative embodiments, the concentration of phosphorus in the phosphorus source in the second solution is 0.8 mol / L to 1.1 mol / L, such as 0.8 mol / L, 0.85 mol / L, 0.9 mol / L, 0.95 mol / L, 1.0 mol / L, 1.1 mol / L, or any range of the above values.

[0041] In some alternative embodiments, the first solvent is at least one of ethanol or water; the second solvent is at least one of ethanol or water.

[0042] In some optional embodiments, in S3, the mixing process involves adding the second solution to the first solution; the addition is preferably done dropwise.

[0043] In some optional embodiments, in S3, the drying temperature is 50℃-110℃, such as 50℃, 55℃, 60℃, 65℃, 70℃, 80℃, 90℃, 100℃, 110℃, etc., or a range of any of the above values; the drying time is 18h-24h, such as 18h, 18.5h, 19h, 19.5h, 20h, 21h, 22h, 23h, 24h, etc., or a range of any of the above values.

[0044] In some optional embodiments, the grinding time is 10 min to 60 min, such as 10 min, 15 min, 20 min, 25 min, 30 min, 35 min, 40 min, 45 min, 50 min, 60 min, or any range of the above values.

[0045] In some optional embodiments, the calcination temperature is 300℃-700℃, such as 300℃, 350℃, 400℃, 450℃, 500℃, 550℃, 600℃, 650℃, 700℃, or any range of the above values; the calcination time is 4h-8h, such as 4h, 4.5h, 5h, 5.5h, 6h, 6.5h, 7h, 7.5h, 8h, or any range of the above values.

[0046] Thirdly, the present invention provides a sodium-ion battery, wherein the sodium-ion battery comprises the sodium-ion battery positive electrode material described in the first aspect or the positive electrode material prepared by the method for preparing the sodium-ion battery positive electrode material described in the second aspect.

[0047] Unless otherwise specified, all experimental steps or conditions in the examples were performed according to conventional experimental procedures and conditions in the art. Reagents or instruments whose manufacturers are not specified are all commercially available products.

[0048] Example 1 This example provides a method for preparing a sodium-ion battery cathode material, including the following steps: (1) Weigh the corresponding mass of sodium hydroxide, vanadium acetylacetonate, manganese acetate, ethyl titanate, and sodium chloride according to the molar ratio of sodium:vanadium:manganese:titanium:chlorine = 4:1:0.9:0.1:0.1, add them to 50 mL of anhydrous ethanol to obtain a first solution, wherein the concentration of vanadium acetylacetonate is 0.6 mmol; (2) Weigh the corresponding mass of anhydrous citric acid according to the molar ratio of carbon:vanadium = 1.5:1, weigh the corresponding mass of phosphoric acid according to the molar ratio of phosphorus atom:vanadium = 2.9:0.9, add them to 10 mL of anhydrous ethanol to obtain a second solution; (3) After stirring the first solution for 10 h, add the second solution dropwise, and after the addition is complete, dry it at 80 °C for 24 h to obtain a solid powder, and grind it for 30 min; (4) Calcine the solid powder obtained in (3) in a tube furnace with argon gas introduced, at a temperature of 650 °C, for a calcination time of 6 h.

[0049] Example 2 This example provides a method for preparing a sodium-ion battery cathode material, including the following steps: (1) Weigh the corresponding mass of sodium carbonate, vanadium acetylacetonate, manganese nitrate, ethyl titanate, and sodium chloride according to the molar ratio of sodium:vanadium:manganese:titanium:chlorine = 4:1:0.9:0.1:0.1, add them to 50 mL of water to obtain a first solution, wherein the concentration of vanadium acetylacetonate is 0.6 mmol; (2) Weigh the corresponding mass of anhydrous citric acid according to the molar ratio of carbon:vanadium = 1.5:1, and weigh the corresponding mass of diammonium hydrogen phosphate according to the molar ratio of phosphorus atom:vanadium = 2.9:0.9, add them to 10 mL of water to obtain a second solution; (3) Stir the first solution for 10 h and add the second solution dropwise. After the addition is complete, dry it at 100℃ for 20 h to obtain a solid powder, and grind it for 30 min; (4) Calcine the solid powder obtained in (3) in a tube furnace with argon gas introduced, at a temperature of 650 ℃, for a calcination time of 6 h.

[0050] Example 3 This example provides a method for preparing a sodium-ion battery cathode material, including the following steps: (1) Weigh the corresponding mass of sodium hydroxide, ammonium metavanadate, manganese oxalate, ethyl titanate, and sodium chloride according to the molar ratio of sodium:vanadium:manganese:titanium:chlorine = 4:1:0.9:0.1:0.1, add them to 50 mL of water to obtain a first solution, wherein the concentration of ammonium metavanadate is 0.6 mmol; (2) Weigh the corresponding mass of anhydrous citric acid according to the molar ratio of carbon:vanadium = 1.5:1, and weigh the corresponding mass of ammonium dihydrogen phosphate according to the molar ratio of phosphorus atom:vanadium = 2.9:0.9, add them to 10 mL of water to obtain a second solution; (3) Stir the first solution for 10 h and then add the second solution dropwise. After the addition is complete, dry it at 80 °C for 24 h to obtain a solid powder, and grind it for 30 min; (4) Calcine the solid powder obtained in (3) in a tubular furnace with argon gas introduced at a temperature of 650 °C for 6 h.

[0051] Example 4 This example provides a method for preparing a sodium-ion battery cathode material, including the following steps: (1) Weigh the corresponding mass of sodium hydroxide, ammonium metavanadate, manganese acetate, tetrabutyl titanate and ammonium chloride according to the molar ratio of sodium:vanadium:manganese:titanium:chlorine=4:1:0.9:0.1:0.1, add them to 50mL of water to obtain a first solution, wherein the concentration of ammonium metavanadate is 0.6 mmol; (2) Weigh the corresponding mass of anhydrous citric acid according to the molar ratio of carbon:vanadium=1.5:1, and weigh the corresponding mass of phosphoric acid according to the molar ratio of phosphorus atom:vanadium=2.9:0.9, add them to 10mL of water to obtain a second solution; (3) Stir the first solution for 10h and add the second solution dropwise. After the addition is complete, dry it at 80℃ for 24h to obtain a solid powder and grind it for 30min; (4) Calcine the solid powder obtained in (3) in a tube furnace with argon gas introduced at a temperature of 650℃ for 6h.

[0052] Example 5 (1) Weigh the corresponding mass of sodium nitrate, vanadium acetylacetonate, manganese carbonate, ethyl titanate and ammonium chloride according to the molar ratio of sodium:vanadium:manganese:titanium:chlorine=4:1:0.9:0.1:0.1, add them to 50mL of water to obtain the first solution, in which the concentration of vanadium acetylacetonate is 0.6 mmol; (2) Weigh the corresponding mass of anhydrous citric acid according to the molar ratio of carbon:vanadium=1.5:1, and weigh the corresponding mass of phosphoric acid according to the molar ratio of phosphorus atom:vanadium=2.9:0.9, add them to 10mL of water to obtain the second solution; (3) After stirring the first solution for 10h, add the second solution dropwise. After the addition is complete, dry it at 50℃ for 24h to obtain solid powder, and grind it for 30min; (4) Calcine the solid powder obtained in (3) in a tube furnace with argon gas introduced at a temperature of 650℃ for 6h.

[0053] Example 6 (1) Weigh the corresponding mass of sodium bicarbonate, vanadium acetylacetonate, manganese acetate, titanium acetylacetonate, and sodium chloride according to the molar ratio of sodium:vanadium:manganese:titanium:chlorine = 4:1:0.9:0.1:0.1, and add them to 50 mL of anhydrous ethanol to obtain the first solution, wherein the concentration of vanadium acetylacetonate is 0.6 mmol; (2) Weigh the corresponding mass of anhydrous citric acid according to the molar ratio of carbon:vanadium = 1.5:1, and weigh the corresponding mass of phosphoric acid according to the molar ratio of phosphorus atom:vanadium = 2.9:0.9, and add them to 10 mL of anhydrous ethanol to obtain the second solution; (3) After stirring the first solution for 10 h, add the second solution dropwise. After the addition is complete, dry it at 120 °C for 18 h to obtain solid powder, and grind it for 30 min; (4) Calcine the solid powder obtained in (3) in a tube furnace with argon gas introduced at a temperature of 650 °C for 6 h.

[0054] Comparative Example 1 This comparative example provides a method for preparing a sodium-ion battery cathode material, including the following steps: (1) Weigh the corresponding mass of sodium hydroxide, vanadium acetylacetonate, manganese acetate and ethyl titanate according to the molar ratio of sodium:vanadium:manganese:titanium=4:1:0.9:0.1, add them to 50mL of anhydrous ethanol to obtain a first solution, wherein the concentration of vanadium acetylacetonate is 0.6 mmol; (2) Weigh the corresponding mass of anhydrous citric acid according to the molar ratio of carbon:vanadium=1.5:1, weigh the corresponding mass of phosphoric acid according to the molar ratio of phosphorus atom:vanadium=2.9:0.9, add them to 10mL of anhydrous ethanol to obtain a second solution; (3) Stir the first solution for 10h and add the second solution dropwise. After the addition is completed, dry it at 80℃ for 24h to obtain a solid powder and grind it for 30min; (4) Calcine the solid powder obtained in (3) in a tube furnace with argon gas introduced at a temperature of 650℃ for 6h.

[0055] Comparative Example 2 This embodiment provides a method for preparing a sodium-ion battery cathode material, including the following steps: (1) Weigh the corresponding mass of sodium hydroxide, vanadium acetylacetonate, manganese acetate and sodium chloride according to the molar ratio of sodium:vanadium:manganese:chlorine=4:1:1:0.1, add them to 50mL of anhydrous ethanol to obtain a first solution, wherein the concentration of vanadium acetylacetonate is 0.6mmol; (2) Weigh the corresponding mass of anhydrous citric acid according to the molar ratio of carbon:vanadium=1.5:1, weigh the corresponding mass of phosphoric acid according to the molar ratio of phosphorus atom:vanadium=2.9:0.9, add them to 10mL of anhydrous ethanol to obtain a second solution; (3) Stir the first solution for 10h and add the second solution dropwise. After the addition is completed, dry it at 80℃ for 24h to obtain a solid powder and grind it for 30min; (4) Calcine the solid powder obtained in (3) in a tube furnace with argon gas introduced at a temperature of 650℃ for 6h.

[0056] Comparative Example 3 This embodiment provides a method for preparing a sodium-ion battery cathode material, including the following steps: (1) Weigh the corresponding mass of sodium hydroxide, vanadium acetylacetonate, and manganese acetate according to the molar ratio of sodium:vanadium:manganese = 4:1:1, add them to 50 mL of anhydrous ethanol to obtain a first solution, wherein the concentration of vanadium acetylacetonate is 0.6 mmol; (2) Weigh the corresponding mass of anhydrous citric acid according to the molar ratio of carbon:vanadium = 1.5:1, weigh the corresponding mass of phosphoric acid according to the molar ratio of phosphorus atom:vanadium = 2.9:0.9, add them to 10 mL of anhydrous ethanol to obtain a second solution; (3) Stir the first solution for 10 h, then add the second solution dropwise, and after the addition is complete, dry it at 80 °C for 24 h to obtain a solid powder, and grind it for 30 min; (4) Calcine the solid powder obtained in (3) in a tube furnace with argon gas introduced, at a temperature of 650 °C, for a calcination time of 6 h.

[0057] In the test examples, the sodium-ion battery positive electrode materials prepared in Examples 1-6 and Comparative Examples 1-3 were used to make positive electrode sheets, and metallic sodium sheets were used as negative electrodes to assemble coin cells. The charge and discharge performance of the sodium-ion batteries prepared in Examples 1-6 and Comparative Examples 1-3 was tested using the Xinwei Battery Test System at a rate of 0.1C and a voltage of 4.2V. The charge and discharge performance of Examples 1-6 and Comparative Examples 1-3 is shown in Table 1.

[0058] The charging cutoff voltage is 2V, and the discharging cutoff voltage is 4.2V; the first cycle is 0.1C charging and 0.1C discharging.

[0059] The charge-discharge performance of Example 1 and Comparative Examples 1-3 was tested at a rate of 20C using the Xinwei Battery Testing System. The results are shown in Figure 1.

[0060] Table 1

[0061] As shown in Table 1, at a rate of 0.1C, the initial discharge specific capacity of the coin cells prepared with the cathode materials prepared in Examples 1-6 is 124.2 mAh g⁻¹. -1 -127.9 mAh g -1 Within the range, all values ​​were higher than the comparative example's 119.2 mAh g⁻¹. -1 -123.5 mAh g -1 The coin cells prepared from the cathode materials prepared in Examples 1-6 had a first-charge specific capacity of 126.3 mAh g⁻¹. -1 -129.5 mAh g -1 Within the range, all values ​​were higher than the comparative example's 123.2 mAh g⁻¹. -1 -125.0 mAh g -1 The capacity retention rate after 50 charge-discharge cycles was 99.73%-99.84%, which was higher than the 99.44%-99.52% of the comparative example. Furthermore, as shown in Figure 1, Example 1 achieved a charge-discharge specific capacity of 71.9 mAh g⁻¹ at a rate of 20C. -1 The charge / discharge specific capacity of comparative examples 1-3 was all below 50 mAh g. -1 This indicates that the sodium-ion battery prepared by titanium-chlorine co-doped sodium-ion battery cathode sheet suppresses the Jan Taylor effect of manganese, reduces the dissolution of manganese at high rates, and greatly improves the battery's capacity and rate performance while maintaining excellent cycle performance.

[0062] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A sodium-ion battery cathode material, characterized in that, The cathode material of the sodium-ion battery is Ti and Cl doped Na4VMn(PO4)3; the molar ratio of Na to Ti in the cathode material of the sodium-ion battery is 4:(0.05-0.1); the molar ratio of Na to Cl in the cathode material of the sodium-ion battery is 4:(0.05-0.1).

2. A method for preparing a sodium-ion battery cathode material, characterized in that, Includes the following steps: S1. Sodium source, vanadium source, manganese source, titanium source, chlorine source and first solvent are mixed to obtain first solution; S2. Mix the phosphorus source, citric acid, and the second solvent to obtain the second solution; S3. The first solution and the second solution are mixed, and then dried, ground and calcined to obtain the positive electrode material of the sodium-ion battery.

3. The method for preparing the sodium-ion battery cathode material according to claim 2, characterized in that, The chlorine source includes at least one of sodium chloride or ammonium chloride; preferably, the titanium source includes at least one of ethyl titanate, titanium acetylacetonate, or tetrabutyl titanate.

4. The method for preparing the sodium-ion battery cathode material according to claim 2 or 3, characterized in that, The sodium source includes at least one of sodium hydroxide, sodium carbonate, sodium bicarbonate, sodium acetate, sodium nitrate, or sodium oxalate; preferably, the vanadium source includes at least one of ammonium metavanadate or vanadium acetylacetonate; preferably, the manganese source includes at least one of manganese acetate, manganese sulfate, manganese nitrate, manganese acetylacetonate, manganese oxalate, manganese carbonate, or manganese oxide.

5. The method for preparing the sodium-ion battery cathode material according to any one of claims 2-4, characterized in that, The molar ratio of sodium, vanadium, manganese, titanium and chlorine in the first solution is 4:1:0.9:(0.05-0.1):(0.05-0.1); preferably, the concentration of vanadium in the first solution is 0.5mol / L-1mol / L.

6. The method for preparing the sodium-ion battery cathode material according to any one of claims 2-5, characterized in that, The phosphorus source includes at least one of phosphoric acid, ammonium dihydrogen phosphate, diammonium hydrogen phosphate, or ammonium phosphate; preferably, the molar ratio of carbon atoms in the citric acid to vanadium in the vanadium source is (1-1.5):(0.5-1); preferably, the molar ratio of phosphorus in the phosphorus source to vanadium in the vanadium source is (2.8-2.9):(0.9-1.0); preferably, the concentration of phosphorus in the phosphorus source in the second solution is 0.8 mol / L-1.1 mol / L.

7. The method for preparing the sodium-ion battery cathode material according to any one of claims 2-6, characterized in that, The first solvent is at least one of ethanol or water; preferably, the second solvent is at least one of ethanol or water.

8. The method for preparing the sodium-ion battery cathode material according to any one of claims 2-7, characterized in that, In S3, the mixing process involves adding the second solution to the first solution; preferably, the addition is done by dripping.

9. The method for preparing the sodium-ion battery cathode material according to any one of claims 2-8, characterized in that, In S3, the drying temperature is 50℃-110℃; the drying time is 18h-24h; preferably, the grinding time is 10min-60min; preferably, the calcination temperature is 300℃-700℃, and the calcination time is 4h-8h.

10. A sodium-ion battery, characterized in that, The sodium-ion battery includes the sodium-ion battery cathode material as described in claim 1 or the cathode material prepared by the method described in any one of claims 2-9.

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